From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Request to obtain granular carbon from the General Electric Co. for a vibration potentiometer.
| Identifier | ExFiles\Box 137\4\ scan0032 | |
| Date | 6th September 1929 | |
| X634. Roy.{Sir Henry Royce} from EFC. EFC/AD.6.9.29. GRANULAR CARBON FOR VIBRATION POTENTIOMETER. In connection with an electrical method of indicating vibration amplitude, will you please obtain for us from the General Electric Co. 6-ozs of Granular Carbon as used in the Granular Carbon Telephone Transmitters, the cost of which, we have ascertained, is 3/- per ounce and delivery 3/4 days. EFC. | ||